To study the etiology and the epigenetic pathways leading to and regulating chronic itch. Similarly, to examine the mechanisms underlying skin changes, including epigenetic alterations while also testing the efficacy of medications, especially topical intervention. In this study, the investigators aim to examine chronic sensory disorder mechanisms related to chronic itch.
Itch was recently identified as one of the top three priority topics in dermatology at a Research Agenda Conference sponsored by the American Academy of Dermatology in 2012. Chronic itch is a complex phenomenon, involving the skin, immune and nervous systems to various degrees. Therefore, focusing on a particular pruritic disease will enable us to work out the underlying pathophysiological mechanisms that occur between the skin and the brain to establish a rational treatment approach. Atopic Dermatitis (AD) is defined as a chronic inflammatory dermatological disease characterized by immunological and neurological cutaneous hyperreactivity with ongoing itch and inflammation. It is linked to an atopic predisposition with skin barrier abnormalities, recurrent delayed-type inflammations; frequently the development of IgE-mediated inhalant and gastrointestinal-related immediate type reactions. It is estimated that the prevalence for AD is at least 17% of the population lifetime worldwide with some reports of increasing prevalence in the last decades. It is also increasingly being observed in the aging population with dry, itchy skin. Various topical and systemic therapies are available and choices are based on disease extent, presence of acute flare, and age of the patient. Unfortunately, itch in AD can be challenging to control; although multiple topical and systemic treatments are available, to date no universally accepted treatment exists. The investigators have previously shown that opioid receptors play an important role in pruritus. Therefore, the investigators plan on expanding on previous and ongoing experiences with opioid antagonists and study the epigenetic and molecular mechanisms behind. Moreover, the investigators have recently discovered that the endogenous opioid ligand Met-Enkephalin influences circadian rhythm by binding directly to CLOCK gene promoters in the nucleus, which then change the amplitude and phase-shift these genes in keratinocytes. Ultimately, the investigators would like to evaluate the effectiveness of topical application of Naltrexone in an effort to potentially help to treat chronic, untreatable itch and learn more about peripheral disorders of sensation (itch and pain).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
QUADRUPLE
Topical naltrexone cream (1%)
Topical placebo cream
University of Minnesota
Minneapolis, Minnesota, United States
Visual Analog Scale for Itching: Circadian 2 Hours AW
To assess the effects of circadian rhythm on pruritus, participants will record itch intensity using a visual analog scale (VAS) at the following time points after waking (AW): AW+2h for 7 days. VAS ranges from 0mm (no itch) to 100mm (unbearable itch). The mean (in millimeters) of 7 daily measurements will be reported.
Time frame: 7 days
Visual Analog Scale for Itching: Circadian 4 Hours AW
To assess the effects of circadian rhythm on pruritus, participants will record itch intensity using a visual analog scale (VAS) at the following time points after waking (AW): AW+4h for 7 days. VAS ranges from 0mm (no itch) to 100mm (unbearable itch). The mean (in millimeters) of 7 daily measurements will be reported.
Time frame: 7 days
Visual Analog Scale for Itching: Circadian 6 Hours AW
To assess the effects of circadian rhythm on pruritus, participants will record itch intensity using a visual analog scale (VAS) at the following time points after waking (AW): AW+6h for 7 days. VAS ranges from 0mm (no itch) to 100mm (unbearable itch). The mean (in millimeters) of 7 daily measurements will be reported.
Time frame: 7 days
Visual Analog Scale for Itching: Circadian 8 Hours AW
To assess the effects of circadian rhythm on pruritus, participants will record itch intensity using a visual analog scale (VAS) at the following time points after waking (AW): AW+8h for 7 days. VAS ranges from 0mm (no itch) to 100mm (unbearable itch). The mean (in millimeters) of 7 daily measurements will be reported.
Time frame: 7 days
Visual Analog Scale for Itching: Circadian 10 Hours AW
To assess the effects of circadian rhythm on pruritus, participants will record itch intensity using a visual analog scale (VAS) at the following time points after waking (AW): AW+10h for 7 days. VAS ranges from 0mm (no itch) to 100mm (unbearable itch). The mean (in millimeters) of 7 daily measurements will be reported.
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Time frame: 7 days
Visual Analog Scale for Itching: Circadian 12 Hours AW
To assess the effects of circadian rhythm on pruritus, participants will record itch intensity using a visual analog scale (VAS) at the following time points after waking (AW): AW+12h for 7 days. VAS ranges from 0mm (no itch) to 100mm (unbearable itch). The mean (in millimeters) of 7 daily measurements will be reported.
Time frame: 7 days
Visual Analog Scale for Itching: Treatment 0 min
To assess the effects of naltrexone 1% or placebo cream on pruritus, participants will record itch intensity using a visual analog scale (VAS) at 0 minutes after applying cream for 3 pruritis attacks in 1 week. VAS ranges from 0mm (no itch) to 100mm (unbearable itch). The mean (in millimeters) over 3 pruritis attacks will be reported.
Time frame: 0 minutes after applying topical cream
Visual Analog Scale for Itching: Treatment 20 min
To assess the effects of naltrexone 1% or placebo cream on pruritus, participants will record itch intensity using a visual analog scale (VAS) at 20 minutes after applying cream for 3 pruritis attacks in 1 week. VAS ranges from 0mm (no itch) to 100mm (unbearable itch). The mean (in millimeters) over 3 pruritis attacks will be reported.
Time frame: 20 minutes after applying topical cream
Visual Analog Scale for Itching: Treatment 40 min
To assess the effects of naltrexone 1% or placebo cream on pruritus, participants will record itch intensity using a visual analog scale (VAS) at 40 minutes after applying cream for 3 pruritis attacks in 1 week. VAS ranges from 0mm (no itch) to 100mm (unbearable itch). The mean (in millimeters) over 3 pruritis attacks will be reported.
Time frame: 40 minutes after applying topical cream
Visual Analog Scale for Itching: Treatment 1 Hour
To assess the effects of naltrexone 1% or placebo cream on pruritus, participants will record itch intensity using a visual analog scale (VAS) at 1 hour after applying cream for 3 pruritis attacks in 1 week. VAS ranges from 0mm (no itch) to 100mm (unbearable itch). The mean (in millimeters) over 3 pruritis attacks will be reported.
Time frame: 1 hour after applying topical cream
Visual Analog Scale for Itching: Treatment 2 Hours
To assess the effects of naltrexone 1% or placebo cream on pruritus, participants will record itch intensity using a visual analog scale (VAS) at 2 hours after applying cream for 3 pruritis attacks in 1 week. VAS ranges from 0mm (no itch) to 100mm (unbearable itch). The mean (in millimeters) over 3 pruritis attacks will be reported.
Time frame: 2 hours after applying topical cream
Visual Analog Scale for Itching: Treatment 3 Hours
To assess the effects of naltrexone 1% or placebo cream on pruritus, participants will record itch intensity using a visual analog scale (VAS) at 3 hours after applying cream for 3 pruritis attacks in 1 week. VAS ranges from 0mm (no itch) to 100mm (unbearable itch). The mean (in millimeters) over 3 pruritis attacks will be reported.
Time frame: 3 hours after applying topical cream
Visual Analog Scale for Itching: Treatment 4 Hours
To assess the effects of naltrexone 1% or placebo cream on pruritus, participants will record itch intensity using a visual analog scale (VAS) at 4 hours after applying cream for 3 pruritis attacks in 1 week. VAS ranges from 0mm (no itch) to 100mm (unbearable itch). The mean (in millimeters) over 3 pruritis attacks will be reported.
Time frame: 4 hours after applying topical cream
Time to Itching Intensity Decrease by 50%
Time to itching intensity decrease by 50% using visual analog scale (VAS) after applying topical cream (either naltrexone or placebo) for 3 pruritis attacks in 1 week. VAS ranges from 0mm (no itch) to 100mm (unbearable itch). VAS will be recorded at 6 time points after application (AA) of cream: 0minAA, 20minAA, 40minAA, 60minAA, 120minAA, 180minAA, and 240minAA. The mean value (in min AA) across 3 pruritis attacks in 1 week will be reported.
Time frame: 4 hours
Total Reduction in Itch Intensity
The total reduction of itch intensity as measured by visual analog scale (VAS) after applying topical cream (either naltrexone or placebo). VAS ranges from 0mm (no itch) to 100mm (unbearable itch). Participants will measure itching via VAS at 0min after cream application and 4hr after cream application. Total reduction in itch will be measured in millimeters on VAS. The mean value (across 3 pruritis attacks in 1 week) will be reported.
Time frame: 4 hours